According to Optimum Tech's review the lack of fans holds back the case's thermal performance. When he changed from AIO to custom cooling the meshlicious beats the m1. So, I think adding one more fan would help thermal performance a bit.
Even when comparing it to 120mm radiators with standalone pump?
This aio with 120mm + 280mm radiator vs barrow cpu block res combo + 280mm radiator, which one do you think has better thermal performance?